This invention broadly relates to electrical devices which contain or include a new positive temperature coefficient resistor (PTCR) composition and the method of manufacturing such devices, as well as the method of preparing such positive temperature coefficient resistor compositions. Such compositions are highly useful for screen printing, for preparation of printed circuits, and for the preparation of numerous different types of electrical devices, as will be discussed hereinafter.
These prior patents involve mixing carbon/graphite with a semi-crystalline polymer which is dissolved in a strong solvent or extruded; or grafting graphite onto a semi-crystalline polymer. The disadvantages to the dissolution approach are that the polymers have poor physical properties and the strong solvents cannot be used in screen printing due to the fact that they will attack the screen emulsion.